Jun 21, 2025 | 22:50 - 00:10 | getting started

Found the datasheet for the microcontroller here: https://docs.nordicsemi.com/bundle/psnrf52840/page/keyfeatureshtml5.html

PMIC datasheet: https://docs.nordicsemi.com/bundle/psnpm1300/page/keyfeatureshtml5.html

Time to go shopping on LCSC (and Digikey for some unavailable parts):

• USB C Receptacle: https://lcsc.com/product-detail/image/GT-USB-7010ASV_C2988369.html
• nRF52840 chip: https://www.digikey.ca/en/products/detail/nordic-semiconductor-asa/NRF52840-QFAA-F-R7/15929801
• nPM1300 chip: https://www.digikey.ca/en/products/detail/nordic-semiconductor-asa/NPM1300-QEAA-R/19722479
• 2.2uH inductor: https://lcsc.com/product-detail/image/ZEMS252012T2R2M_C42462928.html

Jun 22, 2025 | 12:32 - 13:32 | making a pseudo BOM, mostly important parts

Basing from this reference schematic from the nPM1300 datasheet:

Their suggested BOM:

Already picked the inductor yesterday, so let's finish picking the resistors and capacitors.

• 10V 1uF X5R ±10% 0402: https://lcsc.com/product-detail/Multilayer-Ceramic-Capacitors-MLCC-SMD-SMTHRE-CGA0402X5R105K100GTC7503520.html
• 25V 10uF X5R ±10% 0805: https://lcsc.com/product-detail/Multilayer-Ceramic-Capacitors-MLCC-SMD-SMTSamsung-Electro-Mechanics-CL21A106KAYNNNEC15850.html
• 25V 2.2uF X7R ±10% 0805: https://www.lcsc.com/product-detail/Multilayer-Ceramic-Capacitors-MLCC-SMD-SMTSamsung-Electro-Mechanics-CL21B225KAFNNNEC19110.html
• 16V 100nF X7R ±10% 0402: https://www.lcsc.com/product-detail/Multilayer-Ceramic-Capacitors-MLCC-SMD-SMTYAGEO-CC0402KRX7R7BB104C60474.html
• 62.5mW Thick Film Resistor 50V ±100ppm/℃ ±1% 10kΩ 0402 for TWI pull ups: https://www.lcsc.com/product-detail/Chip-Resistor-Surface-MountYAGEO-RC0402FR-0710KLC60490.html
• 62.5mW Thick Film Resistor 50V ±100ppm/℃ ±5% 390kΩ 0402 for initial voltage selection: https://lcsc.com/product-detail/Chip-Resistor-Surface-MountFH-Guangdong-Fenghua-Advanced-Tech-RC-02K394JTC453676.html

Let's wire the schematic for the PMIC!

Since there isn't a symbol for the nPM1300, I guess I will create my own.

Jun 24, 2025 | 12:30 - 16:30 | finished making nPM1300 symbol and wiring

finally done :pff:

since we have 3 led channel, we can use a single RGB LED to get different colors: https://lcsc.com/product-detail/RGB-LEDsTCWIN-TC5050RGBF08-3CJH-AF53AC784540.html

finished wiring the PMIC yay! lets start wiring up the MCU.